Linux Remote-Boot mini-HOWTO: Configuring Remote-Boot
Workstations with Linux, DOS, Windows 95/98 and Win­
dows NT
Marc Vuilleumier Stückelberg, David Clerc
v3.19, February 1999
This document describes how to set up a very robust and secure server-
based configuration for a cluster of PCs, allowing each client to
choose at boot-time which operating system to run. The key of this
configuration is a bootprom based program, which let the user choose
at boot time one of several boot images. This configuration is appli­
cable using InCom TCP/IP Bootprom (add-on for most network cards) or
any PXE-compliant Boot ROM (ready-to-use in most recent PC with built-
in network cards). The most up-to-date version of this document, with
hypertext links to downloadable software and other related materials,
can be found at the address http://cuiwww.unige.ch/info/pc/remote-
boot/howto.html. Linuxdoc-SGML, DVI and PostScript versions are
available in the same directory. If you are interested in getting
info on further developpments, send an E-mail to
David.Clerc@cui.unige.ch.
______________________________________________________________________
Table of Contents
1. Disclaimer and Copyrights
2. What has changed...
2.1 ...since version 2.x ?
2.2 ...since version 3.0 ?
3. Introduction
3.1 Boot ROM and Hard-disk
3.2 The Network
3.3 How it Works
3.4 Related non-commercial documentations
4. The Configuration How-To
4.1 Server-side configuration
4.1.1 Setting up DHCP
4.1.2 Setting up a Proxy DHCP
4.1.3 Setting up TFTP
4.2 Client-side configuration
4.3 Setting Up the Boot Process
4.3.1 Discovering BpBatch
4.4 Setting Up Linux
4.4.1 Configuring the Client
4.4.2 Testing the Configuration
4.4.3 Building the Disk Image
4.4.4 System Maintenance and Upgrades
4.5 Setting up DOS 6 and Windows 3.1
4.5.1 Building the Disk Image
4.5.2 Adapting the configuration for other machines
4.5.3 System Maintenance and Upgrades
4.6 Setting up Windows 95
4.6.1 Setting up a Stand-Alone Client
4.6.2 Building the Disk Image
4.6.3 Adapting the configuration for other Machines
4.6.4 System Maintenance and Upgrades
4.7 Setting up Windows NT
4.7.1 Building the Disk Image
4.7.2 System Maintenance and Upgrades
4.8 Troubleshooting (FAQ)
5. Remote-Boot Tools Reference Manual
5.1 BpBatch, MrBatch and MrZip
5.1.1 Command Line Arguments
5.1.2 Syntax rules
5.1.3 The Cache Filesystem
5.1.4 Special variables
5.1.5 Monitoring commands
5.1.6 Control commands
5.1.7 Keyboard-related commands
5.1.8 Text output commands
5.1.9 Graphics output commands
5.1.10 Security-related commands
5.1.11 Disk-related commands
5.1.12 Boot commands
5.1.13 National language support
5.1.14 Commands specific to MrZip
5.2 NoBreak.sys
6. Special TFTP Servers
6.1 Incom Enhanced TFTP Server
6.2 Linux Enhanced TFTP Server
6.3 The Security Gateway
6.4 The Broadcast TFTP Server
______________________________________________________________________
1. Disclaimer and Copyrights
This document and the related software are provided as is to the Linux
and Internet community, with no form of warranty. Please note that
some operations related in this document may destroy the content of
your hard-disk. We assume no liability for any use, correct or not, of
this document and of the related software.
You are free to do anything you want with the remote-boot tools as
long as you do not make money by selling them or by distributing them
with a commercial product. If you want to commercialize a product
derived from these tools, please contact the authors first to make a
commercial agreement. These remote-boot tools will remain available
for free forever, but we may authorize derived commercial tools.
These provisions shall be interpreted under and in accordance with the
laws of Switzerland, canton of Geneva. All disputes, defenses,
controversies or claims arrising in conncetion with this document and
the related software, shall be subject to the exclusive juridiction of
the courts of the canton of Geneva, Switzerland.
If you like this program, you can send us a Postcard and/or make a
gift to the International Committee of the Red Cross (ICRC) or to the
UNICEF.
2. What has changed...
2.1. ...since version 2.x ?
To say it frankly, almost everything. The underlying concepts are the
same, but the software part has been completly redesigned to overcome
the limitations of previous versions and to make it easier to use. An
highlight of the new features :
· All functions (bpmenu, bpclean, bpunzip) are encompassed in a
single program.
· The program can run not only from the boot rom, but also under DOS,
Windows 95 and Linux.
· The program can now restore images of FAT16, FAT32 and EXT2FS
partitions. If someone want to write NTFS support, let me know...
For now, NT users still have to stick to FAT16.
· The program can not only restore disk images but also add and patch
individual files in order to customize the client behaviour.
· Disk images are not any more bound to 87 MB. They are now file-
system independant archives.
· We provide a mean for automatically downloading a disk image to an
arbitrary big number of clients at the same time (broadcast).
· You can now write your own secure boot script, that will determine
the behaviour of the machine before the real boot.
· You can now boot any Linux kernel, without applying any patch. Its
is also possible to provide a command line and a ramdisk image.
· You can authenticate users at boot time using a Unix, NT or Radius
server and deny them any access to the machine.
· Full national language support is included.
· And many, many other new features...
Is there a program for converting old archives to the new format ?
No, because the internal format is radically different. But you
can easily do the conversion by yourself:
1. Boot an old image (unzip it to your disk)
2. Remove calls to the old unzipreg utility and replace them by
the adequate patch commands (it is very easy, see the
detailed instructions below)
3. Run the new mrzip program to create a new-style disk image
2.2. ...since version 3.0 ?
Version 3.0 was the beta-release. A dozen of sites around the world
have tested it during a month and given much of their time to help us
finding bugs and to suggest enhancements. Thanks to all of them for
their patience, and in particular to Maciek Uhlig, Dick Velders and
Jeff Teeters.
A few minor features have been added since 3.01, such as support for
diskless Linux boot (by disabling the cache).
Version 3.10 introduced compatibility with Intel's Wired for
Management 1.1a NetPC standard. The tools now work with any PXE-
compliant boot ROM (as are most on-board boot ROMs) available today.
Thanks to InCom GmbH for giving us the PXE bootprom that permitted
this developpment. We also succesfully tested the tools with the PXE
Boot ROM that I found incidentally in my Dell computer with onboard
network card (called LanDesk Service Agent).
Version 3.11 to 3.12 added UNIX server-side tools (a PXE Proxy DHCP
server for Solaris and Linux, and an enhanced TFTP server for Linux),
as well as detailled informations on server-side setup and the PXE
booting process.
Version 3.13 added Advanced Power Management support (PowerOff
command).
Version 3.14 added minor enhancements and some corrections. We fixed a
problem with the terminal under RedHat 5.1, and another problem in the
syntax of the "if" command. We added some features suggested by the
Laboratori de Càlcul de la Facultat d'Informàtica de Barcelona (LCFIB)
:
· A new APM variable let you know if your system support the Advanced
Power Management (i.e it supports the poweroff command).
· A "beep" command.
· A new parameter to DrawWindow, to include a title at the window
creation. You can now do DrawWindow 200 200 400 200 "Title".
Version 3.15 added full VESA support. BpBatch now support several
video modes, to accomodate old computers not being able to display
800x600 graphics. A new parameter has been added to InitGraph to
specify the video mode, and a list of detected video mode can be
retrieved from the new VESA-Modes variable.
Version 3.16 fixes the following bugs:
· "Malloc failed" during the Fullunzip process of a multiple
fragments image. Many thanks to Christian Meyer for his
collaboration.
· A bug which prevented the linux version of MrBatch to properly
fullunzip images. This bug was located in the low-level functions
of MrBatch, so it may fix other problems encountered in the linux
version of MrBatch. Many thanks to Jeff Teeters for his
collaboration.
· An error in the codepage translation tables. This bug was found by
the Laboratori de Càlcul de la Facultat d'Informàtica de Barcelona
(LCFIB). You can find the bug report in the BpBatch forum.
Version 3.17 adds some minor features and fixes bugs:
· Fullunzip was turning Extended Memory off
· Booting on the RedHat boot disk now works
· When extracting images with a large number of directories, the
resulting FAT file system was corrupted.
· We added retries to text TFTP transfers. BpBatch will now retry
three times before saying "Could not transfer the file".
· Timestamps are now correctly updated in FAT. (thank to Francis
Chan)
Version 3.18 fixes a bug with the IncrUnzip function. Thanks to Gary
Pike for its collaboration.
Version 3.19 fixed a bug in the error handling of the delete command
on ext2fs, as well as the inappropriate handling of names starting
with A: under Linux. The following new features were also added:
· A new if valid disk:partition syntax can be used to check if a
partition has been formatted
· FAT32 disk images are now fully functional (they now boot properly)
· Linux EXT2 partitions bigger than 2 GB are now supported
· Linux Swap partitions bigger than 128 MB are now supported (this
feature needs a recent kernel, at least 2.1.x)
· FullUnzip is now also possible without a cache partition, by
setting CacheNever to "ON". This might be usefull for a unique
installation, but is not recommended in general is it results in a
high network load.
Thanks to Ruben Schattevoy for its help and contributions to this
release.
3. Introduction
The configuration described here was developped since Summer 1996 at
the CUI, University of Geneva. The Computer Science Department uses
several servers and a number of PCs, which fall into two classes:
· computers devoted to students
· computers devoted to research and teaching assistants
We developped the current configuration with the following aims:
· Every computer should be able to run under Linux, DOS, Windows 3.1,
Windows 95 or Windows NT. One should be able to choose the desired
operating system for each session.
· All softwares, including operating systems, should be take from the
server, in order to facilitate the installations and upgrades.
· Clients computers should be able to run without any write-access on
the server (for security reasons), except for their home directory.
· Client-side configuration should be reduced to its very minimum.
Clients should automatically get their IP configuration parameters
from the server, and this information should be located in a single
file, used for all operating systems.
· Since almost every computer now has a hard-disk, clients should be
able to take profit of it for reducing network load and as
temporary storage space for the user.
· Users must have a login to be able to use any of the computers.
· The login should be the same for all operating system and should
let the user access its unique home directory, common to all
operating systems.
· Student (and secretary :-) computers should be fully cleaned up at
each start. That is, the PC should always look like if it were just
installed.
· Every computer has to be protected from virus attacks.
These constraints lead us to base our configuration on bootprom
tools. We first developped new tools for the excellent TCP/IP
Bootprom from InCom GmbH. Now that a standard for preboot
execution environments as finally emerged, we ported the tools so
that it now also works for any PXE-compliant bootprom. PXE boot
roms, also called LanDesk Service Agent, are now distributed with
almost all on-board network adapter. For more info on PXE and
Intel Wired for Management standard in general, read from
http://www.intel.com/managedpc.
3.1. Boot ROM and Hard-disk
Bootproms exist for quite a long time, but until recently, they were
solely used with diskless computers. Since 1996, this How-to has been
claiming that bootproms are even more interesting for computers which
have a local harddisk, since they allow to take profit of both sides:
· A boot rom make the configurations more robust, since it ensure
that the computer will always boot the same way, no matter any
virus or partition table crash. It can be used, as we did, to
cleanup the harddisk even before the operating system is loaded.
· A local harddisk make the configuration more efficient, since it
can reduce the network trafic through caching, and allows for
efficient swap.
Today, we have the pleasure to see that all computer manufacturers
have come to the same point and provide boot roms as part of new
computer standards.
Note that you can still use the tools described below in an old
fashioned way, that is as a simple kernel/ramdisk loader, even for
diskless computers. However, we do not encourage this use.
3.2. The Network
The University of Geneva owns a class B domain, subdivided into
several subnets. The CUI uses four subnets, among them one is
dedicated to students.
Originally, our PCs were concerned about two network protocols: IPX
and IP. On the IPX side, we used a single Novell Netware 3 server for
sharing software and users files for DOS and Windows. On the IP side,
we used a SUN server for sharing software and users partitions for
Linux, with NFS.
In our latest configuration, we do not any more use IPX. There is a
single Unix server (which could be Linux as well as a SUN), sharing
software and user files using NFS for Linux clients and using SMB
(NetBIOS) over TCP/IP for Dos and Windows clients. In this way, we
have a single home directory used by all operating systems.
3.3. How it Works
1. When a client PC is turned on, it first performs the traditional
system checks before the TCP/IP Bootprom or PXE Boot ROM takes the
control.
2. The bootprom issues a BOOTP/DHCP request in order to get its IP
configuration parameters.
3. If the server knows the PC issuing the request, it will send back a
BOOTP/DHCP reply with informations such as the client's IP address,
the default gateway, and which bootdisk image to use.
4. In case of a PXE boot ROM, there might be some more exchanges
between the client and the server to determine installation
parameters.
5. The bootprom then downloads the boot image from the server using
the TFTP protocol. The boot image happens to be a small program
called bpbatch, our boot-time batch file interpreter.
6. The batch interpreter is started. At this time, it is almost alone
in the computer memory. There is no operating system loaded, except
the preboot execution environment (offered by the Boot ROM).
7. The batch interpreter look in the BOOTP/DHCP reply for command-line
options, and in particular for the name of the batch to execute.
8. According to the instructions in the batch file, it will for
instance:
a. Load a national keyboard mapping
b. Authenticate the user according to a remote server (Unix, Radius
or Windows NT)
c. Let the user choose between the available operating systems
d. According to the operating system choosen, repartition the hard-
disk and quick-format some partitions
e. Check if an up-to-date compressed image of the selected OS is
present at the end of the disk. If not, it download it using
TFTP
f. Uncompress the selected OS to the main partition
g. If the selected OS is Linux, load a kernel and start it
h. If the selected OS is DOS or Windows, simply let the computer
boot on its fresh new hard-disk
For DOS and Windows 3.1, we use the freely available Microsoft Lan­
Manager for DOS (search the network for the mirror nearest to you;
the distribution consists of three files named disk1 to disk4) as
SMB client. Microsoft LanManager supports dynamic configuration
using DHCP. After logging in, the user is faced to DOS, and can
start Windows 3.1 by typing the traditional win command. Note that
at this point, DOS and Windows 3.1 appear to be installed locally.
For Windows 95 and Windows NT, we also use Microsoft SMB client
(called Client for the Microsoft Network), that supports dynamic
configuration using DHCP. We reduce network load using Shared LAN
Cache, a nice and powerful network-to-disk cache program.
Students computers can be turned off the hard way at any time with­
out risks, since the hard disk is reinitialized at each start.
For "safe" computers (ie. for assistants computers), once the computer
has been booted once using the above described system, the boot script
simply redirect the boot to the local hard-disk, without cleaning it
again. This allow users to leave data on their local hard disk. But
whenever the configuration gets corrupted, the user can simply choose
from the boot menu in order to have a fresh installation.
3.4. Related non-commercial documentations
This configuration has been successfully reproduced at several places
around the world. A few people have written some hints and tricks that
complement this How-To. If you did so and that your page is not
already referenced in this documentation, please send an e-mail to
Marc.VuilleumierStuckelberg@cui.unige.ch. And if you experience
problems while reproducing this configuration, have a look at these
pages !
· http://www.br.fgov.be/RESEARCH/INFORMATICS/info/bootp.html, by
Alain Empain of the Belgium National Botanic Garden. Many useful
sample scripts, and a nice PERL program to automatically generate
graphic menus and corresponding HTML documentation from a higher
level description.
· http://www.katedral.se/system/elevsyst, by Johan Carlstedt of The
Cathedral School of Uppsala, Sweden. At this day, the
configuration described at this place is still based on the
previous version of the remote-boot tools. However, almost
everything remains applicable, given a few changes.
· http://vitoria.upf.tche.br/~fred/, in portuguese, by Frederico
Goldschmidt of the Passo Fundo University, Brasil.
· http://www.etse.urv.es/~larinyo, in spanish, by Lluis Arino, of
the Escola Tecnica Superio d'Enginyeria, Spain.
You can also send me your BpBatch script if you want me to include it
in the sample scripts collection.
4. The Configuration How-To
First, arrange to have the following two machines within arm's reach:
· the server, usually a Unix or Windows NT machine
· the client, a PC with a bootprom enabled, and nothing valuable on
the hard disk.
If you want to test the configuration but you do not yet have a
bootprom, you can download the TCP/IP BootProm demo diskette from
InCom GmbH at http://www.incom.de. This diskette will make your
computer behave like if it had a TCP/IP Bootprom plugged in.
If you already have a Boot ROM, you need to enable it. If you are
using Incom TCP/IP Bootprom, you can do that using a special program
from your network card manufacturer. If you have a PXE Bootprom, you
can do it simply from BIOS setup, by changing the default boot device.
For student computers, we configured the boot on network first, and
disabled hard-disk and floppy-disk boot. For assistant computers, we
also configured network-boot first, but we allow hard-disk and floppy-
disk boot.
4.1. Server-side configuration
On the server, you will need the following services:
1. A BOOTP/DHCP server
2. May be a Proxy DHCP server
3. A TFTP server
Note for PXE Boot ROM users: We found after severals hours of
tedious search that PXE Boot ROMs with version before 0.99 do not
follow the IP protocol and discard all packets that have the Don't
Fragment (DF) flag set. That means, you will have to disable Path
MTU Discovery on the server, or the Boot ROM will not see any of
its packets. On Solaris, use ndd /dev/ip ip_path_mtu_discovery to
see if you have it enabled and ndd -set /dev/ip
ip_path_mtu_discovery 0 to disable it. However, this fix only
works for non-broadcast packets (ask SUN why...). That means, it
will work for TFTP but not for DHCP :-(. Intel has recently fixed
this bug, and if you bought your computer after June 1998, you
surely have a corrected PXE implementation.
4.1.1. Setting up DHCP
The role of the DHCP server is to give to the client an IP address and
to make it load the file named bpbatch.P from the TFTP server. DHCP
is a superprotocol over BOOTP. If you are using InCom TCP/IP Bootprom,
you may live without DHCP (using an old BOOTP server).
On Windows NT, you will probably use the native DHCP server. If you
are using InCom TCP/IP Bootprom, you will have to use a special trick
to specify the boot file name (get more info from InCom WWW site). If
you are using a PXE Bootrom, you will need a Proxy DHCP server, but no
other trick is needed as the boot file name will be provided by the
Proxy DHCP server.
On Linux, the best choice is the standard DHCP server from the
Internet Software Consortium. If you are using a PXE Bootrom, in
addition to the usual options, you will need to add the following
ones:
· option dhcp-class-identifier "PXEClient"
· option vendor-encapsulated-options ff;
On Solaris, you can either use the Internet Software Consortium DHCP
server (available on the Web), or use Solaris DHCP server (available
since Solaris 2.5). However, as Solaris DHCP server does not seems to
be able to insert a client class identifier in its DHCP offer, you
must install a Proxy DHCP server. Morever, this Proxy DHCP server must
reside on another computer since Solaris DHCP server locks the DHCP
port.
We suggest giving infinite lease time for remote-boot clients. Don't
forget that BOOTP/DHCP requests are bounded by subnets. If the client
and the server do not reside on the same subnet, you should install a
BOOTP/DHCP Relay agent on any computer between the two. For now, just
assume that both machines are on the same subnet.
4.1.2. Setting up a Proxy DHCP
The role of the Proxy DHCP server is to overcome limitions of some
DHCP servers and to provide PXE specific extensions. A proxy DHCP
server only makes sense for a PXE Boot rom.
As BpBatch itself is quite powerfull, you wont need to use any PXE
specific DHCP extension (menus, etc.). However, if your DHCP server
is not able to show minimal PXE compliance, you will need a Proxy DHCP
server or your PXE Boot ROM will not accept to go further.
On Windows NT, you can try to use Intel WfM PDK (available from their
web site), but it is not very easy to use. We rather suggest having a
Linux machine on the subnet and using our small Proxy DHCP. The major
advantage of our Proxy DHCP Server for BpBatch is that our server will
let you specify an option 155 vendor tag that will be interpreted by
BpBatch as a command line.
On Linux and Solaris, you can run our Proxy DHCP program, that simply
takes as argument the TFTP server IP address, boot file name and
optional arguments, and does everything for you. If the DHCP port on
the server is already requested by another daemon, the proxy DHCP
server will run on port 4011. In this case, it is necessary that the
other daemon on DHCP port answer a DHCP offer with client class
PXEClient so that the PXE client knows that it must try on port 4011.
If you want to understand better PXE extensions to DHCP, there is an
extensive description available on Intel WWW site. However, be warned
that the documents are quite confusing, as the protocol has been
extended to a number of optional stages, in order to allow for a
maximal flexibility. The key to understand it is that all what a PXE
client needs is a complete enhanced DHCP answer. If it receives only a
standard DHCP offer, it will look further until it gets
1. a client class (T60) set to PXEClient
2. vendor encapsulated options (T43) (possibly empty, ie. hex ff)
3. a non-empty boot filename
The PXE specific negociation ends as soon as all these infos are
received, but can lead to a very complex process (install server
discovery, etc.) if some are missing.
4.1.3. Setting up TFTP
The TFTP server is a very simple file server. In its basic version,
TFTP use 512 bytes data blocks, which are quite inefficients. InCom
TCP/IP Bootprom and PXE Boot ROMs allow to use larger blocks (1408
bytes), which speeds up transfers a lot. However, this can only work
with an enhanced TFTP server.
On Windows NT, we suggest using InCom enhanced TFTP server, available
on their web site.
On Linux, you can use our enhanced TFTP server, available at
http://cuiwww.unige.ch/info/pc/remote-boot/soft/etftpd.tar.gz.
On Solaris, you should use InCom enhanced TFTP serer, available on the
utility disk provided with the TCP/IP Bootprom.
If you prefer using a standard TFTP daemon, remove the P in all boot
image name extensions, in order to tell the Bootprom to use only the
standard TFTP port (This trick was introduced by InCom GmbH for the
TCP/IP Bootprom. We still use it as an easy way to select the default
TFTP port with PXE bootproms).
4.2. Client-side configuration
First, we will do set up the part common to all operating systems, ie.
the batch-file interpreter. Then, for each operating system, we will
go through the following steps:
1. Setup a stand-alone client
2. Save its configuration on the server
3. Test it as a remote-boot client
4. Adapt it so that it works for any similar client machine
Once this is done, you will be able to setup any supplemental
client just by plugging a Boot ROM in it (or buying a Wired for
Management ready computer...) and adding one line in the DHCP
configuration file.
Our examples assume that you have a hard disk of 1.4 Gb or more. If
you have less, reduce the sizes of the partitions, but remember the
you need to leave a few hundreds megabytes unallocated (that is, the
last partition must not take up to the last cylinder) to leave free
room for the special cache partition. Moreover, as the cache always
starts at the cylinder following the last allocated cylinder, if you
do not use the same total size for all your tests, you will have to
download several times the same files (the cache will be automatically
cleared).
Never despair. If you can't get it to work, first look in the
Troubleshooting section if your problem is not already solved (get the
latest version from the Web). Then, take a look in the BpBatch forum.
Perhaps someone else had the same troubles as you have, and the answer
can be found in the forum. Forum's URL :
http://cuiwww.unige.ch/info/pc/remote-boot/forum/. If it still does
not work, think about monitoring network traffic for network related
problems (use tcpdump on Linux or snoop on Solaris). If you really
cannot get it to work, you can send an E-mail to
David.Clerc@cui.unige.ch or Marc.VuilleumierStuckelberg@cui.unige.ch.
If your problem is strictly related with the remote-boot configuration
and if we are not overflowed, we will try to solve your problem.
4.3. Setting Up the Boot Process
Get the BpBatch software, either as .zip or as .tar.gz. The
executables are available at
· http://cuiwww.unige.ch/info/pc/remote-boot/soft/bpb-exe.zip
· http://cuiwww.unige.ch/info/pc/remote-boot/soft/bpb-exe.tar.gz
The source code (Assembler and C) is also available on request.
In the server /tftpboot directory, put the following three special
boot images, which together make our pre-boot batch file interpreter:
· bpbatch.P, the dynamic loader (respect the uppercase !)
· bpbatch.ovl, the relocated interpreter
· bpbatch.hlp, the on-line help file
Then add an entry in the DHCP configuration file for your client,
with the boot file set to "bpbatch.P". Define a vendor option tag
155 (decimal) with the value "-i" (on the standard DHCP server,
this is done by the following command: option option-155 "-i";). It
is interpreted by bpbatch as the command line, and -i stands for
"interactive".
Boot the client computer. You might shortly see
· The Boot ROM copyright
· The string DHCP while the client waits for a DHCP reply
· The string TFTP while the client waits for the first TFTP packet
· The string Loading BpBatch while the loader download the
interpreter
· And finaly our banner, followed by a nice greather-than prompt
Congratulations ! You have started the batch interpreter... If you
are curious about what you can do with it, continue reading the
next section. If you are on a hurry, skip it and go directly
install the operating system of your choice. If you have any doubt
about a command within the interpreter, type help.
Note that you can run the same interpreter within DOS and Linux by
running the MrBatch program. There are a only very few differences
(the Linux version do not have graphics support and the DOS version
can only send BOOTP and TFTP requests if the BootProm is not hidden by
the operating system).
It may be a good idea to read now the section about the Syntax Rules
of BpBatch, and in particular the paragraphs on File References and on
The Cache Filesystem. This will help you understand the examples.
Once all operating systems will be set up, you will have to make a
menu to let the user choose the one he wants. You should be able to
discover by yourself how to make such a menu. All necessary commands
are documented at the end of this document.
4.3.1. Discovering BpBatch
Try to type LogVars. You should get about thirty variables listed.
Roughly, the first are BpBatch settings, then come all parameters
extracted from the BOOTP/DHCP reply, and the last variable is a list
of disks sizes, in Megabytes.
Type GetPartitions part, then LogVars again. There should be one more
variable containing the list of defined partitions on your first hard-
drive. Assuming that the first partition is either BIGDOS, FAT32 or
LINUX-EXT2, try LogDir "{:1}" to get the content of the root
directory, then LogDir "{:1}/usr" if there is an usr directory. You
can even try LogTree "{:1}/etc" to get a directory tree.
Put a GIF file (format GIF-87a, interlaced or not, but NOT GIF-89a) on
your TFTP server. We will suppose that the file is named image.gif.
You can copy it wherever you want with the following command: Copy
"image.gif" "{:1}/temp/image.gif". Or you can use it directly from the
server. Now type Logvars "V*" and look at the value of the VESA
variable. If it is On, which is most probable, that means you have a
VESA-compliant video adapter. You can list the available video modes
using Echo "$VESA-Modes". To display your image try the following
command: DrawGif "image.gif". The image should be on the upper left
corner of the screen. You can draw it on another place by specifying X
and Y coordinates after the image name. You can also draw text with
DrawText 200 200 "Hello world" yellow. Or draw an empty window with
DrawWindow 200 200 300 150. To insert a title when you create a new
window, try DrawWindow 200 200 300 150 "My Window". When you are
tired of graphic mode, simply type CloseGraph.
Note on graphics : by default, all graphical routines work in the
800x600 VESA mode (with 256 colors), which is the first field of the
VESA-Modes variable. If you want to use a different video mode, change
the variable in order to have the requested video mode as the first
field of the list.
Now take a text editor, and create a file named test.bpb in the
tftpboot directory with the following content:
______________________________________________________________________
:again
DrawWindow 150 200 400 160 "Identity check"
TextAttr Black LightGray
At 15,20 Print "Username : "
Input username 8
At 17,20 Print "Password : "
Getpasswd userpass 8
if "$username" != "smith" goto again
if not "$userpass" match-passwd "BpR8oiIlRR9bo" goto again
#
clear
DrawWindow 200 200 150 100 green blue "Congratulations"
DrawText 220 250 "You got it !" yellow
WaitForKey 3
CloseGraph
interact
______________________________________________________________________
In your BOOTP/DHCP configuration, change the option-155 from "-i" to
"test", and reboot the client computer. The small script should run
automatically, and ask you for a username and password. If you do not
type smith and justdoit, you wont be able to boot the computer. Later
you will learn how to use a Unix, NT or Radius server to check valid
user names.
4.4. Setting Up Linux
In order to set up Linux, you will need to boot the floppy disk
provided with the RedHat Linux distribution. BpBatch includes a
command that can redirect the boot to the floppy: FloppyBoot.
Set up RedHat Linux on your client, with network support, and any
packages you may want. You may want to recompile the kernel to better
fit your hardware, but it is not necessary.
4.4.1. Configuring the Client
It is probably a good idea to include BOOTP support to the kernel, so
that you do not have to customize the client IP address manually.
In order to reduce network load, you might also want to setup the
filecache for caching on the hard disk files that are loaded by NFS.
Roughly, the principle of the filecache is that whenever a symbolic
link from the cache subdirectory is followed, it is replaced by its
target. If the target is itself a subdirectory, each entry of the
subdirectory becomes a symbolic link to the original entry of the
foreign filesystem. The filecache has been written by Unifix GmbH,
and is part of Unifix Linux 2.0. It is freely distributable, and you
can get the necessary files from
http://cuiwww.unige.ch/info/pc/remote-boot/soft/filecache.tar.gz. In
order to use the filecache, you have to
· apply a patch to the kernel (file patch-filecache), enable
filecache support through make config or whatever you prefer, and
recompile the kernel
· copy the filecache binary file to /sbin
· create a mount point called /mnt/nfs (using mkdir)
· copy filecache.conf to /etc. This file contains the following
lines:
Max 100 MB 50 % #
Cache /mnt/nfs/usr /usr
Cache /mnt/nfs/opt /opt
· copy the content of /usr and /opt to the server, export them read-
only with anon=0 (for allowing root access) and mount them under
/mnt/nfs (add a line for that in /etc/fstab)
· rename /usr as /usr.orig
· link /usr to /mnt/nfs/usr
· rename /opt as /opt.orig
· link /opt to /mnt/nfs/opt
· ensure that /usr and /opt are not empty and contains the correct
directories
· recursively remove /usr.orig and /opt.orig
· copy filecache.init to /etc/rc.d/init.d
· And finally link /etc/rc.d/rc3.d/S35filecache to
/etc/rc.d/init.d/filecache.init
If you successfully followed each of these steps, you should have
the filecache working next time you boot, as long as you do not
forget to use your patched kernel.
4.4.2. Testing the Configuration
Copy your compressed kernel image (zImage, bzImage, vmlinuz or
whatever you call it) to the server /tftpboot directory as linux.krn.
If you had to unplug the bootprom from the PC, you can now plug it
again. When BpBatch starts, type LinuxBoot "linux.krn" "root=/dev/hda1
BOOT_IMAGE=linux" (assuming that the root ext2 filesystem is on the
first partition). Alternatively, if you did setup your configuration
on a computer without bootprom, just boot let it boot using the loader
you installed (lilo, ...). But in the later case, if you want the
filecache to work, you should have explicitely installed your kernel
with filecache support at the right place.
Wait until the system comes up. If you installed the filecache, you
can check that /usr has exploded into a directory with some symlinks
and some already-exploded directories. Now start the programs that the
end-users will use most of the time, in order to load them once for
all to the hard disk.
You can still make adjustements to your configuration, like on any
stand-alone linux station.
4.4.3. Building the Disk Image
When you are happy with your configuration, login as root, go to the
/tmp directory and run our mrzip program. MrZip is a command
interpreter like BpBatch, but it can understand more commands than
BpBatch does. In particular, it can understand the following commands:
______________________________________________________________________
showlog
filter -"tmp/*"
filter -"var/log/*"
fullzip "/" "/tmp/linux.imz"
______________________________________________________________________
This will create a disk image in /tmp/linux.imz. Move it to the server
/tftpboot directory. Then copy the following batch file to /tftp­
boot/linux.bpb:
______________________________________________________________________
hidelog
setpartitions "linux-ext2:992 linux-swap:32"
fullunzip "linux.imz" 1
clean 2
linuxboot "linux.krn" "root=/dev/hda1 BOOT_IMAGE=linux"
______________________________________________________________________
The BOOT_IMAGE argument is to stay compatible with lilo for RedHat 5.1
and later rc.sysinit.
Your remote-boot linux configuration is ready ! You can now either set
the BOOTP-option-155 to "linux", or type include "linux.bpb" from
within BpBatch to test it.
4.4.4. System Maintenance and Upgrades
If you want later to upgrade software, install bug fixes and security
fixes, proceed as follow:
· Remote-boot a client computer to get a fresh linux install
· Make your changes
· Redo the disk image
· Copy the new image in place of the old one on the server
That means, you can upgrade software on your server-based
configuration as if it were a purely local install.
4.5. Setting up DOS 6 and Windows 3.1
On the client computer, boot on your favorite dos floppy disk (either
remove the bootprom or type FloppyBoot within BpBatch). Format the
dos partition of your hard-drive with the /S option, in order to put
the operating system on it. The size of the partition is not
important, as disk archives created with MrZip Create a DOS
subdirectory, copy DOS in it. Install your favorite network client
(for instance Microsoft LanManager), Windows 3.1, and so on. If you
use Microsoft LanManager, do not use DHCP for the IP configuration as
it is a very poor implementation that will almost surely fail with
reasonable network load. To do that, add the following lines in your
protocol.ref file, in the section that loads tcptsr (of course,
replaces the xxx by your true IP parameters):
IPADDRESS0 = xxx xxx xxx xxx
SUBNETMASK0 = 255 255 xxx xxx
DEFAULTGATEWAY0 = xxx xxx xxx xxx
DISABLEDHCP = 1
Do not be afraid to use EMM386 to optimize the memory usage, and even
to include the area where you put your network adapter ROM, since it
is not used anymore at this time. But carefully exclude the network
adapter RAM, or you will not be able to connect to your server. Use
the NOEMS parameter.
If you want to ensure that the client machine cannot be used without a
valid login name, download our nobreak pseudo-device driver (available
at http://cuiwww.unige.ch/info/pc/remote-boot/soft/nobreak.zip) and
run it at the beginning of your config.sys. Then add something like
this to your autoexec.bat:
______________________________________________________________________
rem -- we use the dummy file c:\logged as a flag
del c:\logged >nul
:loginneeded
cls
echo Please type in your login name and password
echo.
net logon *
rem -- the login script should have created c:\logged
if not exist c:\logged goto loginneeded
del c:\logged
rem -- now enable break again
echo Yes >NOBRK
______________________________________________________________________
Ensure that your client boot well by rebooting the client and
evaluating the following commands within BpBatch interactive mode:
HideBootprom
HdBoot
4.5.1. Building the Disk Image
On the server, make a share called admin for instance, on which you
will put some stuff for the system administrator. If the server is a
Unix machine, it is a good opportunity to put in admin a softlink to
the /tftpboot subdirectory, so that you can put images in it directly
from the client. Within admin, create a /utils subdirectory and put
the following files in it:
· mrbatch.exe, the DOS version of BpBatch
· mrzip.exe, the DOS version of the program for building disk images
· bpbatch.hlp, the on-line help file
You might also like to put in the same directory a simple MrZip
script named zipdos.mrz file that contains the commands needed for
building a DOS image, like this one:
______________________________________________________________________
showlog
filter -"lanman.dos/lmuser.ini"
filter -"temp/*"
filter -"*.swp"
fullzip "c:/" "L:/tftpboot/dos.imz"
______________________________________________________________________
Now go back to your client, mount the admin volume on drive L:, go to
your utils directory and type the following command:
mrzip -b zipdos
One minute later, you will have a new file in the server /tftpboot
subdirectory called dos.imz, which is a compressed image of your hard
disk. Copy the following batch file to /tftpboot/dos.bpb:
______________________________________________________________________
hidelog
setpartitions "bigdos:1024"
setbootpart 1
fullunzip "dos.imz" 1
hidebootprom
hdboot :1
______________________________________________________________________
Your remote-boot DOS configuration is ready ! You can now either set
the BOOTP-option-155 to "dos", or type include "dos.bpb" from within
BpBatch to test it.
4.5.2. Adapting the configuration for other machines
If you want to customize some settings according to the machine,
typically the IP settings since Micro$oft DHCP is buggy, you can setup
BpBatch to change some files before booting. Firsti go to the
lanman.dos directory and do
copy *.ini *.ref
Then edit the .ref files and replace all fixed parameters with BOOTP
variable names as in the following examples:
computername = ${BOOTP-Host-Name}
ipaddress0 = ${MS-IPAddress}
subnetmask0 = ${MS-IPSubnet}
defaultgateway = ${MS-IPRouter}
Then rebuild the disk image as previously. Note that for IP parame­
ters, we do not use the BOOTP variables directly because LanManager
needs then as space-separated numbers instead of dot-separated num­
bers. Change dos.bpb to the following:
______________________________________________________________________
hidelog
setpartitions "bigdos:1024"
setbootpart 1
fullunzip "dos.imz" 1
set MS-IPAddress="$BOOTP-Your-IP"/.= /
set MS-IPSubnet="$BOOTP-Subnet-Mask"/.= /
set MS-IPRouter="$BOOTP-Routers"/.= /
patch "{:1}lanman.dos/protocol.ref" "{:1}lanman.dos/protocol.ini"
patch "{:1}lanman.dos/tcpputils.ref" "{:1}lanman.dos/tcputils.ini"
patch "{:1}lanman.dos/lanman.ref" "{:1}lanman.dos/lanman.ini"
hidebootprom
hdboot :1
______________________________________________________________________
If you prefer, you can also put the .ref files in the server /tftpboot
directory instead of in the disk image.
We like to be able to easily change the computers configuration
without rebuilding the image. To do that, copy your autoexec.bat and
config.sys as autoexec.ref and config.ref to the server /tftpboot and
add the following two lines to the batch file above:
patch "autoexec.ref" "{:1}autoexec.bat"
patch "config.ref" "{:1}config.sys"
You can then freely change the files and even customize them with
machine-dependant values obtained from BOOTP.
After making any change to the client machine configuration, do not
forget to rebuild the disk image using mrzip if you want to preserve
your changes.
4.5.3. System Maintenance and Upgrades
If you want later to add new software or change anything else, proceed
as follow:
· Remote-boot a client computer to get a fresh install
· Make your changes
· Redo the disk image
· Copy the new image in place of the old one on the server
That means, you can upgrade software on your server-based
configuration as if it were a purely local install.
4.6. Setting up Windows 95
In previous versions of this document, we used the Microsoft server-
based installation of Windows 95, but it was really too much pain and
not much worth:
· It is very, very bogus
· Many software package do not support it and their install will
fail. Among them, Microsoft Internet Explorer, OnNet 32, Novell's
Protected-mode client (which is MUCH more secure than Microsoft
Client for Netware).
· It cannot be used with the Microsoft Network client over TCP/IP,
since Microsoft provides no real-mode driver for TCP/IP compatibe
with Windows 95. That means, it cannot be used with Samba
· It makes software upgrades almost impossible since every client
turned on will lock many DLLs on the server, and thus produce
sharing violations if you try to upgrade them.
Consequently, we throwed away of this document all the informations
and bug-workaround collected during months (you can still find them
as a HTML document at http://cuiwww.unige.ch/info/pc/remote-
boot/win95old/win95old.html) and turned to our new disk-based
remote-boot concept. Basically, the configuration for Windows 95
is now almost as easy the configuration for DOS.
4.6.1. Setting up a Stand-Alone Client
Setup a regular Windows 95 client, either starting from scratch as
explained in the configuration of a DOS client, starting from the DOS
client and installing over the network (that is what we did). You can
also start with a preconfigured Windows machine, but you will probably
have less knowledge of what stuff is on the hard disk.
Proceed as described above for a DOS client. It is usually NOT
necessary to use EMM386 with Windows 95. If you are using Windows 95
OSR2 (alias MSWIN 4.1, alias Windows 95 service pack 1, alias Windows
95 with Internet Explorer), you should add the following line in the
[Options] section of MSDOS.SYS (yes, it is a text file):
______________________________________________________________________
AUTOSCAN=0
______________________________________________________________________
This will let Windows know that you do not want ScanDisk to be runned
automatically at boot time.
If you want to reduce network and server load (which will improve your
system performances) while keeping all softwares on the server, you
should consider installing the excellent Shared LAN Cache, from
Measurement Techniques, Inc (see http://www.lancache.com). This
software runs on each client computer, and caches to the local hard
disk every data obtained from the network. Even MS-Office starts much
faster the second time you run it... You need one license per client
computer, but it is not very expensive, and the firm make special
prices for universities and colleges. The best thing to do is to go to
their Web site and download the free evaluation copy.
4.6.2. Building the Disk Image
Your MrZip script will be named zipwin95.mrz and contain:
______________________________________________________________________
showlog
filter -"temp/*"
filter -"*.swp"
fullzip "c:/" "L:/tftpboot/win95.imz"
______________________________________________________________________
To build the image, mount the admin volume on drive L:, go to your
utils directory and type the following command:
mrzip -b zipwin95
A few minutes later, you will have a new file if the server /tftpboot
subdirectory called win95.imz, which is a compressed image of your
hard disk. If your compressed image was bigger than 87 MB, it has
probably been splitted in two or more fragments. These fragments will
automatically loaded one after the other when needed. Note that an
image bigger than 87 MB will usually take More than one minute to
uncompress and may irritate your users. Our Windows 95 image is only
70 MB big, because most software (except Office and Explorer)
completely reside on the server. Only 45 seconds are needed to
uncompress the image and restore the full disk.
Copy the following batch file to /tftpboot/win95.bpb:
______________________________________________________________________
hidelog
setpartitions "bigdos:1024"
setbootpart 1
fullunzip "win95.imz" 1
hidebootprom
hdboot :1
______________________________________________________________________
Your remote-boot Windows 95 configuration is ready ! You can now
either set the BOOTP-option-155 to "win95", or type include
"win95.bpb" from within BpBatch to test it.
4.6.3. Adapting the configuration for other Machines
The big difference between Windows 3.1 and Windows 95 is that the
later includes code for Plug-and-play , ie. automatic detection of
your hardware. This not a bad thing in itself, but the trouble is that
it is often too sensible, and that it sometimes fails.
If you try to start another client with exactly the same boot image,
you will probably get several messages during startup telling that
Windows has detected new hardware: a new sound card, a new hard-disk,
a new network card, and even a new mouse... There can be two reasons
for that:
· the devices may not use the same ressources (for instance the mouse
is not connected on the same port, or the sound card is not
connected in the same slot - yes, that is detected)
· the devices may tell to Windows 95 their personal serial number
(for instance, every Windows 95 differenciate every network card on
the basis of its world-wide unique ethernet address)
The fact that Windows 95 discover that the hardware has changed may
not be a problem if the plug-and-play works as-is, but it become a
problem when the plug-and-play does not work. For instance, Windows
95 plug-and-play for our Logitech PS2/aux mouse does not work, and
result in no mouse at all. To solve such kind of problems, arrange
to have all computers as similar as possible, or make different
images for different hardware. Later, you will discover that you
can simply use the same image and just have several copies of the
registery, that you can copy after having restoring the disk image
but before booting.
The thing you cannot avoid to differ between computers is the network
card. PCI cards usually do not mind, but ISA Plug and Play do. Bad
luck for us, the plug-and-play code for our SMC EtherEZ card hangs the
computer. The only solution is to let Windows 95 believe that it
already know the network card, and that it is not necessary to trigger
plug-and-play. The trick for doing that is to automatically insert an
entry for the network card in Windows 95 registery, before starting
it. Note that this trick is not any more needed with most PCI cards.
Move the autoexec.bat to the server as described above for DOS. Edit
it (on the server) and add the following lines:
rem --- Patch Windows registery in order to avoid plug-and-play detection
regedit /L:c:\windows\system.dat /R:c:\windows\user.dat c:\temp\patch.reg
regedit is a standard Windows 95 program that let you browse the reg­
istery if you start it from within Windows 95, or do simple operations
on the registery if you call it from DOS. Run regedit under Windows
95, search for your network card, usually under
HKEY_LOCAL_MACHINE\Enum\ISAPNP
and export the branch using the File menu. This will create a text
file, that you should same as patch.ref in the server /tftpboot dire­
tory. Edit this file and find out where the card ethernet address is
stored (do that on two different machines and compare the files if you
can't find it by yourself). Replace it by a pettern in the form
${MACID}. Then add lines to the win95.bpb script like this:
set macid = "$BOOTP-Client-ID"
patch "patch.ref" "{:1}temp/patch.reg"
(do any necessary string manipulation for setting MACID if it is not
exactly the client Ethernet address). That's all, your clients should
not any more try to autodect the network card.
Once again, this whole trick is not necessary when using PCI network
adapters. Incidentally, we can use the same mechanism for
automatically configuring the hostname, which Windows 95 does not seem
to take into account when configuring through DHCP. We just add the
following line to our patch.ref file:
______________________________________________________________________
[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\VNETSUP]
"ComputerName"="${BOOTP-Host-Name}"
[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP]
"HostName"="${BOOTP-Host-Name}"
[HKEY_LOCAL_MACHINE\System\CurrentControlSet\control\ComputerName\ComputerName]
"ComputerName"="${BOOTP-Host-Name}"
______________________________________________________________________
Using this small registery trick, your configuration should normally
be portable for all machines with similar configurations. If you
cannot avoid that Windows detect some hardware as new on one machine,
try to rebuild the disk image from this machine. This will include the
registery configuration specific to this machine into the image, and
hopefully supress the problem.
4.6.4. System Maintenance and Upgrades
If you want later to upgrade software, install bug fixes and security
fixes, proceed as follow:
· Remote-boot a client computer to get a fresh install
· Make your changes
· Redo the disk image
· Copy the new image in place of the old one on the server
That means, you can upgrade software on your server-based
configuration as if it were a purely local install.
4.7. Setting up Windows NT
We do not use Windows NT for remote-boot client computers but we have
tested our system to ensure that it work as well. And it works.
As our utilities currently have no support for NTFS (we neither have
the documentation nor the time to do that, but I would be happy to
help anyone who is interested in doing it), you will have to install
NT on FAT16 (simply do not convert your partitions to NTFS during the
setup).
Copy your win95.bpb boot script to winnt.bpb. Change the
setpartitions line in winnt.bpb to the following:
setpartitions "BIGDOS:512 BIGDOS:512"
Then boot Windows 95 using this script, and install your NT client on
drive C. Do not worry about the second partition for now. Do not
install too much stuff, or you will get a really large and slow-to-
uncompress image. Remove Windows 95 from the disk disk C, you do not
need it in a Windows NT image (the boot menu is handled by the boot­
prom, not by NT boot loader).
Reboot your computer in without overwriting the hard disk, ie. do not
execute the winnt script but just
hidebootprom
hdboot
Your NT station should start-up correctly. Make any necessary cus­
tomization.
4.7.1. Building the Disk Image
The trouble with Windows NT is that direct disk access is prohibed by
the kernel. That means, MrZip will not even be able to read the boot
sectors. The best way to do an image is then to boot Windows 95 and to
run MrZip from a DOS window. To do that, change the winnt.bpb script
so that the Windows 95 image is not restored on the first but on the
second partition:
______________________________________________________________________
hidelog
setpartitions "BIGDOS:512 BIGDOS:512"
setbootpart 2
fullunzip "win95.imz" 2
hidebootprom
hdboot :2
______________________________________________________________________
(if you have any supplementary patch, change the "{:1}" to "{:2}").
Boot with this script; you should have Windows 95 running, but a new
drive D: should be available, with Windows NT inside.
Make your disk image as usual (but on D:, of course), and save it as
winnt.imz on the server /tftpboot directory. Edit one last time the
winnt.bpb script like this:
______________________________________________________________________
hidelog
setpartitions "BIGDOS:512 BIGDOS:512"
setbootpart 1
fullunzip "winnt.imz" 1
clean 2
#fullunzip "win95.imz" 2
hidebootprom
hdboot :1
______________________________________________________________________
Your Windows NT remote-boot configuration is ready. Of course, if you
do not like to have two partitions, you can setup a single partition
instead. But when you have to rebuild the image, you will have to
setup the second partition again for booting Windows 95.
4.7.2. System Maintenance and Upgrades
If you want later to upgrade software, install bug fixes and security
fixes, proceed as follow:
· Remote-boot a client computer to get a fresh install
· Make your changes
· Edit winnt.bpb: comment the clean and winnt fullunzip, uncomment
win95 fullunzip
· Redo the disk image
· Copy the new image in place of the old one on the server
That's all, folks !
4.8. Troubleshooting (FAQ)
This section lists most frequently encountered problems.
The image download never ends
You are probably using a standard TFTP server, and it cannot
handle more than 65535 packets of 512 bytes (or even 32767
packets for the Solaris server). That is, your image must be
fragmented in pieces of no more than 30 MB (or 15 MB for
Solaris). See under CopyArchive for instructions on fragmenting
an existing image. But you should seriously thing about using
InCom's extended TFTP server, as it is much more efficient (it
uses packets of 1408 bytes instead of 512 bytes).
The archive decompression fails immediately
There are three possibilities. Either the image is really
corrupted on the server (try use MrZip to see if it is the
case), or the file transfer has failed because of TFTP timeout,
or because of incompatible protocol.
TFTP timeout occurs when the network is too heavily loaded (for
instance if you try to download a huge image with more than four
clients at a time). In this case, BpBatch does not retry
indefinitely because it would not help. Shut down a few
computers and retry with no more than four computers (or maybe
even three). If you often need to download images for a lot of
computers, you can try our special Broadcast TFTP server (see
the section dedicated to it).
Incompatible protocol is caused by using a standard TFTP server
(typically the one built-in in your UNIX server) while asking
BpBatch to work with enhanced TFTP. If you use a standard TFTP
server, you should remove the .P extension (see the explanation
in the next question).
The computer hangs instead of downloading/unzipping (1)
If you are using Incom's TFTP server, try to add -s 1408 59 to
the command line. If you are not using an enhanced TFTP server,
remove the .P extension from BpBatch filename on the server and
in bootptab.
Detailed explanation : this problem occurs if you did not setup
an extended TFTP server but you used bpbatch.P as the
bootfilename DHCP/BOOTP tag. BpBatch will indeed try to connect
to an extended TFTP server when the bootfilename ends with a .P
extension. To solve this problem, you can either remove the .P
extension at the end of the bootfilename (it will tell BpBatch
to use standard TFTP) or install an extended TFTP server. The
only supported extended TFTP server today is the one provided by
Incom. You can find compiled binaries on their web site, or on
our distribution directory. For Incom's TFTP server to properly
work with the extended TFTP feature, you must add -s 1408 59 to
the command line.
The computer hangs instead of downloading/unzipping (2)
May be your computer has a bad VESA support. Try giving the -v
command-line argument or setting the VESA variable to "OFF".
VESA scrolling is broken
We use a VESA 1.1 function for scrolling. If your video adapter
does not support VESA 1.1, forget it. If the scrolling works for
one page, but then produces a strange strippled pattern, do not
worry. This is a known bug, I will fix it as soon as I have time
for it (VESA scrolling is not really essential...)
There is a corrupted file in the cache
When a file in the cache is corrupted by an external program, it
is automatically removed from the cache. When a file in the
cache is not fully written (because the computer is turned off
during the file transfer), it is also automatically removed. But
if the server transmits a corrupted file or if the transfer
aborts from the server side, it is possible that this file stays
in the cache. You can clean-up the cache simply by holding both
shift down while BpBatch access it for the first time.
Alternatively, you can evaluate clean -1 in interactive mode.
The EXIT command does not work in a batch file
This is not a bug. Exit is not a command. There is no exit or
quit command because it does not make any sense to exit from a
boot script without booting. And MrBatch is really the same
program as BpBatch. What you can do instead is calling HdBoot.
This makes sense, and the DOS version will cleanly exit instead
of rebooting. Note that you can exit from the DOS version at
any time by pressing Ctrl-Break. This will restore all hooked
interrupts before leaving.
The Print command does not print
If you try to print something and immediately enter interactive
mode, you may not see your text. This is because your text was
written on the runtime screen and the Interact command has
switched the display to the Log screen. Just put a GetKey after
the print commands and you will see the text output.
MrZip says Malloc failed
MrZip needs a lot of conventional memory to run. If you
encounter this problem, first ensure that you have unloaded the
bootprom either using HideBootprom or using InCom's bputil. If
you run MrZip from bare MS-DOS (not within Windows 95 DOS box),
you should use EMM386 to load the network drivers high in order
to get as much conventional memory as possible. From a Windows
95 DOS box, there is usually no problem (as long as you have not
left your old 16-bit stuff in your autoexec.bat when you
installed Windows 95).
MrZip aborts while reading directories
This bug has already been fixed once. Get the latest release of
MrZip. If the problem persists, try to build your image with
Trace set to "ON" (and usually PauseLog set to "OFF"); this will
let you discover which file causes the problem. Send a detailled
bug report.
MrZip cannot access some file
MrZip is probably trying to read a locked, open or special file,
such as Windows swap file. Such files should usually not be
included in the image and should be filtered out (using the
filter command). It is also possible that the operating system
is playing you a trick. If MrZip does not tell you what file
causes the problem, try to build your image with Trace set to
"ON" (and usually PauseLog set to "OFF"). You can also try to
use direct disk access (that is, do not refer the source
partition as "C:" or "/" but as "{:1}" or whatever partition it
is). Using direct disk access is usually slower because we have
less buffers than the operating system, but it may be sometimes
more reliable.
Disk images are always reloaded from the server
Disk images are stored in the special cache area and should not
be reloaded if they have not changed on the server. However, as
the cache area always starts after the last used partition,
changing the total size of partitions will move the location of
the cache and thus destroy its content. Another possible reason
for a file disappearing from the cache is that the previous file
has grown more than one-and-an-half times its initial size. The
file would then have been overwritten and need to be downloaded
once again. This should almost never occurs. A third possible
reason is a too small cache area. If the free space left outside
the partitions is less than one-and-an-half times the sum of all
compressed image sizes, only the most recently used images will
be present in the cache and the other will have to be reloaded
on demand.
Red Hat Linux 5.1 does not boot properly
This distribution assumes Linux was booted using lilo and checks
for the BOOT_IMAGE command line argument (in
/etc/rc.d/rc.sysinit). Simply add it in the linuxboot call, or
change your rc.sysinit.
The broadcast TFTP ramdisk hangs (Got in bound state)
Linux dhcp client is a program that dynamically changes the IP
address of the client according to DHCP offers. If the address
is offered forever (infinite lease time), the DHCP client just
set the address and returns (this is what we expect). However,
if the lease time is limited, the DHCP client must remain loaded
and ask for new addresses every few minutes. And if the DHCP
client does not return, MrBatch will never be loaded... The
solution is to give an infinite lease time (sometimes encoded as
-1).
File access hangs under BpBatch, but not under MrBatch
This problem occured on an AMI BIOS dated 94/07/25. We
investigated a little bit, and found no solution. It seems that
this problem is due to a bug in this BIOS (some register or
memory location must be destroyed).
Unzip of a fragmented archive fails (Malloc failed)
This problem was introduced with PXE compatibility, but has now
been fixed. Please get the latest version.
MrBatch and MrZip complain about the terminal under RedHat 5.x
This problem has been fixed in the 9th of August version of
MrBatch/MrZip. There was a problem with a new version of
ncurses which has been released with RedHat 5.1.
MrZip has been linked to the version 3.0 of libncurses. You can
use other versions of libncurses only if they are newer than
version 3.0. To use a newer libncurses, all you have to do is to
create a soft link from libncurses.so.3.0 to your
libncurses.so.xx file. With RedHat 5.1, you can use the
following command : cd /usr/lib ; ln -s libncurses.4.2
libncurses.3.0 You can also download a version recent version of
mrzip/mrbatch. Starting from the 10/25/98, mrbatch is now
compiled under RedHat 5.1.
MrBatch and MrZip do not start under Linux (file not found)
This problem is the reverse of the previous one. Now that the
distribution is libc6 ready, it cannot be used any more with
libc5. If you encounter this problem, simply upgrade your Linux
box (Well, if we hear too much complaints, we might try to keep
two distributions...).
I can not access other mode than the default 800x600 VESA mode
You should first display the contents of the VESA-Modes
variable, to see if your hardware support the mode you would
like to use. Then, try one of the two ways to select a special
VESA mode :
· InitGraph "mode": Try InitGraph "1024x768", and then run the
graphical primitive you are interested in (e.g DrawGif).
· VESA-Modes: The first field of the VESA-Modes variable is the
name of the default mode. If you change the VESA-Modes variable,
all graphical primitive will use the mode you specified.
BpBatch prints a
We corrected a bug in the memory allocation functions of
BpBatch. You should make sure that you have a version of BpBatch
which has been released after september the 22nd 1998.
Fullunzip using the Linux version of MrBatch always fails
We corrected this problem in the 09/22/1998 release.
Scandisk says my disk is corrupted
The 10/25/98 release did correct a problem with large images.
Try to download a recent version of BpBatch.
My RedHat boot floppydisk does not work with FloppyBoot
This bug has been corrected in the 10/25/98 release.
My FAT32 disk image does not boot properly
This bug has been corrected in the 02/09/99 release.
5. Remote-Boot Tools Reference Manual
This section provides detailled informations on the use of the tools
we developped at the CUI, University of Geneva for this remote-boot
configuration.
5.1. BpBatch, MrBatch and MrZip
These three names stand for three variants of the same program, with
the following characteristics:
· BpBatch is a special program that can be started from the BootProm
before the operating system is loaded. It is made of two parts:
bpbatch.P, the dynamic loader, and bpbatch.ovl, the program itself.
BpBatch has full disk I/O capabilities through our own
implementation of FAT16, FAT32 and Ext2fs, as well as remote
network I/O capabilities through the BootProm TFTP API. BpBatch
was compiled under DOS using Borland C 5.0 and Turbo Assembler 3.2.
· MrBatch is the DOS/Linux version of BpBatch. All commands
recognized by BpBatch are recognized by MrBatch and vice versa.
This is very usefull if you want to test your batch scripts from a
DOS/Linux session. Under DOS, MrBatch emulates remote I/O by OS-
based file access if the bootprom is not available. Under Linux,
the bootprom cannot be seen anymore but MrBatch can emulate it
using Linux IP support, or use OS-based file access. MrBatch was
compiled under Linux using GCC 2.7.2.1 and under DOS using Borland
C 5.0 and Turbo Assembler 3.2.
· MrZip is an interpreter that recognizes a superset of MrBatch
language, and that serves to build disk images. In MrZip, the
limited remote file I/O is replaced by a full-featured OS-based
file access. MrZip does not include VESA support. MrZip was
compiled under Linux using GCC 2.7.2.1 and under DOS using Borland
C 5.0 and Turbo Assembler 3.2.
5.1.1. Command Line Arguments
All programs accept the same syntax of arguments. MrBatch and MrZip
take them from the command line, while BpBatch look for them in the
BOOTP option 155 (decimal). Here is the syntax of the arguments:
[-x] [-l] [-b] [-v] [-w] [-i] [script-basename]
where:
· -x disable the use of extended memory
· -l disable the use of ISO-latin-8859-1 as default character set
· -b cancel the bootprom detection (which cause a floppy seek under
DOS)
· -v cancel the VESA detection (which cause a switch to full screen
under Windows 95)
· -w enable direct disk write access (disabled by default under DOS
and Linux)
· -i enable interactive mode even if a script name is provided
The script-basename is optional. If provided, MrBatch and BpBatch
load the file with the .bpb extension, and MrZip loads the file
with the .mrz extension. If not provided, MrBatch and MrZip run in
interactive mode while BpBatch loads the file with the same
basename as the BOOTP Boot file and a .bpb extension.
5.1.2. Syntax rules
The following rules apply when BpBatch parses an input line.
· Commands are parsed line by line. Lines are separated by CR and/or
LF.
· The maximal line length is currently 255 characters.
· Keywords and variable names are case-insensitive.
· " is interpreted as the special string delimiter
· When ${variable} or $variable is encountred, it is substituted by
the value of the variable, or by an empty string if the variable is
undefined. The substitution also occurs within a string. Moreover,
the resulting substituted value must be explicitely enclosed
between double quotes if used as a string value (ie. one should
merely speak of macro expansion than of a variables).
·
· \a is substituted by the audible-bell character (ASCII 7)
· \b is substituted by the backspace character (ASCII 8)
· \n is substituted by the newline character (ASCII 10)
· \r is substituted by the return character (ASCII 13)
· \t is substituted by the tabulation character (ASCII 9)
· \v is substituted by the vertical-tab character (ASCII ...)
· \nnn where n is a 3-digit octal number between 000 and 377 is
substituted by the character with ascii code specified
· \X where X is any other character not listed above is substituted
by X itself. In particular,
· \" is substituted by a regular double-quote (not a string-
delimiter)
· \$ is substituted by a regular dollar sign (not variable
substitution)
· \\ is substituted by a regular backslash (not a special character)
· The character "end of string" (ASCII code 0) CANNOT be used
anywhere as it is used internally as end-of-string delimiter
· The character "floating diaeresis" (ASCII code dec 249, hex F9,
octal 371) CANNOT be used in any string as it is used internally as
string delimiter in the input parsing routine.
· The character "block space" (ASCII code dec 255, hex FF, octal 377)
CANNOT be used in any variable value as it is used internally as
variable delimiter.
Empty lines are ignored. Lines starting with a sharp (#) are treated
as comments and are not interpreted. Lines starting with a column (:)
are treated as labels and are not interpreted.
String expressions
Strings are delimited by opening and closing double-quotes:
"Hello world"
To include double-quotes within a string, quote them using a back­
slash:
"I said: \"Hello world\""
Strings can be postfixed with a few operators.
· The character substitution operator:
"Hello world"/o=u/ == "Hellu wurld"
"198.76.54.32"/.= / == "198 76 54 32"
· The word selection operator (zero-based):
"Hello world"{0} == "Hello"
"198 76 54 32"{1-3} == "76 54 32"
· The substring selection operator (zero-based):
"Hello world"[4] == "o"
"Hello world"[4-7] == "o wo"
Operators can be chained by postfixing one after the other. For
informations about the string length and word count operators, see
under "Numerical expressions".
Numerical expressions
Numerical expressions work on 32-bits integer numbers (from
-2,147,483,646 to 2,147,483,647). Hexadecimal octal and binary
numbers are not understood. Whenever a numerical expression is
expected, the following are recognized:
· A positive or negative integer number
· An expression in the form (expr1 op expr2) where op can be
either +, -, * (multiply), / (divide) or % (modulo) and expr is
a numerical expression. Note that EACH operation MUST be
enclosed between parenthesis :
((3 * 5)+2) == 17
· The string-length operator (@), followed by a string :
@"Hello world" == 11
· The word-count operator (#) followed by a string :
#"Hello world" == 2
Durations
A few commands expect durations as arguments. Durations are
measured in seconds, with a precision of up to a tenth of
second:
Delay 3 waits for 3 seconds
Delay 0.3 waits for 3/10 seconds
Colors
Whenever a color is expected, you can either use the numeric
value of the color or its symbolic name (case-insensitive). The
following colors are recognized
Black 0
Blue 1
Green 2
Cyan 3
Red 4
Magenta 5
Brown 6
LightGray 7
DarkGray 8
LightBlue 9
LightGreen 10
LightCyan 11
LightRed 12
LightMagenta 13
Yellow 14
White 15
File References
File names are strings. They must therefore always be enclosed
between double-quotes. File names are case-sensitive on case-
sensitive filesystems, case-insensitive on case-insensitive
filesystems. Slash and backslash can be freely used one in
place of the other. Do not forget to double backslash since a
single backslash is an escape character.
There are two kinds of file references:
· Direct disk files
· Foreign files
Direct disk files are referenced using the following notation:
"{disk:partition}/absolute/filename"
The disk number can be omitted and defaults to zero. For instance,
"{:1}/usr/bin" points to /usr/bin assuming there is such a direc­
tory on the first partition. Direct file I/O is solely based on our
own file access routines (we do not use the operating system).
There are two special partitions. Partition zero corresponds to the
hard disk master boot record (MBR) and has a pseudo file-system
which let you access the boot code. Partition minus-one (-1)
corresponds to the cache filesystem (see below).
Under BpBatch/MrBatch, foreign files correspond to remote files on
the TFTP server when the BootProm is available:
"help.bpb" is the file help.bpb in the /tftpboot directory
"gifs/MyImage.gif" is a file in /tftpboot/gifs
Other TFTP servers can be referenced :
"198.76.54.32:help.bpb"
If the other server is behind a gateway :
"198.70.0.1/198.76.54.31:help.bpb"
One can also specify a specific port for the TFTP connection :
"198.76.54.32@89:getpasswd/smith"
There can be only one open remote file at a time. If the BootProm
is not available, remote files are emulated using the operating
system file I/O, but the same restriction apply.
Under MrZip, foreign files correspond to files as seen by the
operating system. There is no limitation, and foreign files can be
used wherever direct disk files can be. Foreign files are usually
faster than direct disk files, because the operating system has
more buffers. Foreign files can refer to network files if supported
by the operating system.
"C:\\autoexec.bat"
"C:/config.sys"
"/mnt/net/usr"
5.1.3. The Cache Filesystem
In order to reduce network load and to fasten the boot process, disk
archives, linux kernels and possibly other files are cached on the
hard disk. This disk cache is located at the end of the hard disk,
between the last cylinder allocated in the partition table and the
last physical cylinder of the disk (out of any allocated partition).
There MUST be room between the last partition and the end of the disk
if you want the cache filesystem to work. The cache filesystem MUST
work if you want to restore a disk image.
The disk cache is organised in a volatile, CRC-validated filesystem :
Each directory entry and each 32 KB data block is validated by a
32-bits CRC. Whenever a directory entry or a data block unexpectedly
changes, the file is automatically removed from the cache and
downloaded again upon the next request.
You can freely access the cache filesystem from within BpBatch,
MrBatch and MrZip using direct disk access on the special partition
"{:-1}". To see the content of the cache, just type :
logdir "{:-1}"
If the cache ever gets corrupted and is not automatically cleaned
(which should never occurs), you can either type :
clean -1
(in interactive mode) or hold both shifts down when BpBatch access the
cache for the first time.
5.1.4. Special variables
Some variable are initially set and/or have special meanings. Some of
them exist within all programs, other are only available under MrZip
and other are only available when a BOOTP/DHCP reply has been
received.
General variables
· $Program is set to "BpBatch" within BpBatch, "MrBatch" within
MrBatch and "MrZip" within MrZip
· $Basename is set to the basename of the script on which the
batch interpreter was started
· $HelpFile is the name of the file loaded when Help is invoked.
Default: "${Basename}.hlp"
· $BOOTP-... are variables set from the BOOTP/DHCP reply (see the
paragraph on BOOTP/DHCP variables for more details)
· $DHCP-... are variables set from the DHCP reply (see the
paragraph on BOOTP/DHCP variables for more details)
· $Disks is set to the space-separated list of sizes for each
disk. That means, #"$Disks" represent the number of disks and
"$Disks"{0} is the size of the first disk
· $Keypressed is set to the next ready-to-read key available in
the keyboard buffer (if available)
· $LBA controls the use of LBA to access disks > 2Gb. Default:
"ON"
· $FDA controls the use of fast disk access (write accross
cylinders). Default: "ON"
· $VESA controls the use of VESA graphics. Default: "ON" if
available
· $VESA-Modes gives the list of all available VESA modes. The
first entry of the list is the default mode, which is used when
no parameter is given to InitGraph. Note: if VESA="OFF", this
variable is blank
· $APM is set to "ON" if your computer supports Avanced Power
Management. If $APM is "ON", you can use the command PowerOff to
turn your computer off. Default: depends on your hardware
· $Trace controls the display of each command before execution. It
also controls the display of file names when creating new
archives. Default: "OFF"
· $AutoShowLog controls the automatic switch to the text log
whenever the ESC key is pressed. Default: "ON"
· $PauseLog controls the pause between each page of log when the
log is visible. Default: "ON"
· $CacheDisk is set to the disk used for caching remote files.
Default: empty == 0, the first hard disk
· $CacheAlways controls the automatic caching of remote files
copied, patched or drawn as GIF. Default: "OFF"
· $CacheNever prevents any file from being cached. Turn this
variable on for diskless Linux boot. Default: "OFF"
· $CacheReserve controls the preventive allocation of 25 percent
more space than necessary in the cache partition, to let the
files grow. Turn this variable off if you are short of disk
space. Default: "ON"
· $ExtMemory controls the use of Extended Memory (or XMS). Once
deactivated, extended memory cannot be reactivated. Default:
"ON" if available
· $IsoLatin controls the interpretation of upper ASCII codes in
included and patched files. The IsoLatin settings are processed
at the time the file is loaded, not at the time the file is
processed. Default: "ON"
· $ProgressX and $ProgressY controls the position of the progress
window displayed in VESA graphics during archive download and
decompression. Default: 200 200
· $EXT2-Backup controls the update of superblock backups in Linux
ext2 filesystem. Superblock backups take a few seconds to do and
are never used by current kernels (only by e2fsck).
· $Security-Gateway controls the gateway-server used for user
authentication. Our special authentication gateway must be
running on the target computer. Default: "${BOOTP-Server-
IP}@89" (ie. the TFTP server, on port 89)
· $Security-Check contains the answer of the security server for
the last check performed, either PASSED or FAILED. Default:
"FAILED"
· $Security-Passwd, $HelpTopic, $OnExit, $OnKey-... are used
internally.
See also BOOTP variables and MrZip-specific variables.
MrZip-specific variables
The following variables are only used within MrZip.
· $TempPath controls the directory where temporary files will be
stored. Default: == current directory
· $DumpFormat controls the way archives are dumped to the log when
requested. It is a string containing
· "h"/"H" to display the archive header
· "b"/"B" to summarize/dump boot sectors
· "s"/"S" to display a short/long allocation summary
· "d"/"D" to display a short/long directory listing
· "f"/"F" to summarize/dump files
Default: "hbD"
· $FragmentSize controls the size of archive pieces. If you do
not use InCom's extended TFTP server, you should set this to "30
MB". Default: "87 MB"
· $SourceArchive, $DestArchive, $Filter... are used internally.
BOOTP variables
The following BOOTP-... and DHCP-... variables are recognized,
as long as a BOOTP/DHCP reply has been received (TCP/IP Bootprom
must be reported as detected):
$BOOTP-Client-ID
$BOOTP-Your-IP
$BOOTP-Server-IP
$BOOTP-Gateway-IP
$BOOTP-Bootfile
$BOOTP-Server-Name
$BOOTP-Subnet-Mask
$BOOTP-Time-Offset
$BOOTP-Routers
$BOOTP-Time-Servers
$BOOTP-Name-Servers
$BOOTP-Domain-name-Servers
$BOOTP-BOOTP-Log-Servers
$BOOTP-Cookie-Servers
$BOOTP-Lpr-Servers
$BOOTP-Impress-Servers
$BOOTP-Resource-Location-Servers
$BOOTP-Host-Name
$BOOTP-Boot-Size
$BOOTP-Merit-Dump
$BOOTP-Domain-Name
$BOOTP-Swap-Servers
$BOOTP-Root-Path
$BOOTP-Extensions-Path
$BOOTP-IP-Forwarding
$BOOTP-Interface-MTU
$BOOTP-All-Subnets-Are-Local
$BOOTP-Broadcast-Address
$BOOTP-NIS-Domain
$BOOTP-NIS-Servers
$BOOTP-NTP-Servers
$BOOTP-Font-Servers
$BOOTP-X-Display-Manager
$DHCP-IP-Address-Lease-Time
$DHCP-Message-Type
$DHCP-Server-Identifier
$DHCP-Message
$DHCP-Renewal-Time
$DHCP-Rebinding-Time
$BOOTP-NIS+-Domain
$BOOTP-NIS+-Servers
$BOOTP-Server-Name
$BOOTP-Bootfile
$BOOTP-Mobile-IP-Agent
$BOOTP-SMTP-Servers
$BOOTP-POP3-Servers
$BOOTP-NNTP-Servers
$BOOTP-WWW-Servers
$BOOTP-Finger-Servers
$BOOTP-IRC-Servers
$BOOTP-StreetTalk-Servers
$BOOTP-STDA-Servers
Other BOOTP/DHCP parameters can be used under the name
$BOOTP-Option-n
where n is the decimal representation of the BOOTP option number.
Do not mix-up BOOTP-Gateway-IP, which is the gateway to use for
TFTP and should be 0.0.0.0 if the TFTP server is in the same
subnet, and BOOTP-Routers, which contains the default IP
gateway(s). The TCP/IP Bootprom sometimes seems to set the value of
BOOTP-Gateway-IP from the value in BOOTP-Routers, causing each TFTP
ack packet to be sent to the router first. To avoid such behaviour,
if your TFTP server is in the same subnet as the client, force
BOOTP-Gateway-IP to 0.0.0.0 (thanks to Maciek Uhlig for having
pointed out this problem).
5.1.5. Monitoring commands
This section lists commands for monitoring the system state. Optional
arguments are listed between parenthesis (I would have prefered square
brackets, but LaTeX do not like them at this place...)
Interact
Show the log and turn to interactive mode until QUIT or EXIT is
entered. Type HideLog before quitting if you want to avoid
disturbing log messages during batch execution.
Help (topic)
Load the on-line help file (bpbatch.hlp) and display the
description of the given topic. If no topic is provided, or if
the topic is unknown, display the help index.
Log
Display the string on the log. No return/linefeed is implicitely
added.
Echo
Display the string on the log and go to the next line.
Equivalent to
Log "text\r\n".
LogVars (
Log (ie. display on the log) all variables matching the given
pattern. The pattern can contain wildcards (? and *).
Example: LogVars "BOOTP-*" list all BootP variables
LogDir
Log (ie. display on the log) all files from the given path that
match the pattern. The pattern can contain wildcards (? and *).
Example: LogDir "/usr/g*p" list files names like g...p
LogTree
Log the directory tree starting with the given path as root.
LogFile
Log the content of the file. The file must be no more than 64 KB
big.
ShowLog
Make the log visible if it was hidden. Automatically performed
when ESC is pressed with "$AutoShowLog" == "ON" and when
entering interactive mode.
HideLog
Prevent log messages to appear on the screen. Default state when
BpBatch, MrBatch and MrZip are started on a script file.
CaptureLog
Record all log output to a 64 KB buffer until EndCapture is
issued. Wrap around buffer if the log output is more than 64 KB
big. This command can be used to create a text file with an
arbitrary content. The EndCapture MUST occurs within the same
batch file.
EndCapture (
End up the capture of the log. If a filename is given, store the
captured text to a file. Otherwise, discard it.
Beep
Make a sound. This command is equivalent to Echo "\007".
5.1.6. Control commands
This section lists commands that control the batch execution.
Optional arguments are listed between parenthesis.
Include
Load the given file and start up the parser on it. Go back to
the current point when the include file processing is done. The
interpretation of characters above ASCII 127 within the include
file depends on the value of $IsoLatin at the time the file is
included.
OnExit command
Setup an exit-handler that will automatically be evaluated at
the end of current batch file.
Goto label
Move the execution cursor to the given label (ie. the line
starting with :label)
Eval
Perform all substitutions on the "command" and run the parser on
it.
If ...
If (not) (==|!=||>=|<=|=>|=)
If (not) (ci) "str1" (==|!=||>=|<=|=>|=) "str2"
If (not) (ci) "str1" Match-Expr "pattern"
If (not) (ci) "str1" Match-Passwd "unix-passwd"
If (not) (ci) "str1" in "wordlist"
If (not) (ci) "str1" in-file "filename"
If (not) exist "filename"
If (not) valid :
These commands execute command; if the test succeeds. The 1st form
compares two numerical expressions. The 2nd form compares two
strings, optionally case-insensitive. The 3rd form tests if "str1"
matches the given pattern (wildcards allowed). The 4th form tests
if the clear password "str1" matches the Unix-crypted password.
The 5th form tests if "str1" is included in the word list. The 6th
form tests if "str1" is included in the word file. The 7th form
tests if the given file exists. The 8th form tests if the given
partition is valid (i.e. formatted). This form is only supported by
BpBatch versions after February 1999.
Set ...
Set variable = "string-value"
Set variable =
Setup a value for the given variable. If the given value is a
numerical expresison, it will be implicitely converted to a string.
A variable can be used anywhere by refering it as $variable or
${variable}. If the resulting reference is to be interpreted as a
string, it should be enclosed between double quotes: "$variable" or
"${variable}".
Delay duration
Waits until the specified duration (expressed in seconds)
expired. See also the paragraph on the format of durations.
GetTime variable, GetDate variable
Get the CMOS time and store it into variablein the form
HH:MM:SS. Get the CMOS date and store it into variablein the
form YY/MM/DD. This can be used to customize the behavior of
your boot scripts depending on the time of day or on the date.
SetTime
Set the computer CMOS time or date to the given value. If you
have a security gateway (our special TFTP server) running, you
can automatically adjust the CMOS time and date of the client
computers at each boot by evaluating the following command:
include "$Security-Gateway:gettime"
If you want to understand what this command does, just type:
logfile "$Security-Gateway:gettime"
Poweroff
Turn off the computer. This command only works if the computer
is Advanced Power Management (APM) compatible.
5.1.7. Keyboard-related commands
This section lists commands that let you monitor the keyboard input.
Optional arguments are listed between parenthesis. See also under
National Language Support.
GetKey (variable)
Indefinitely wait until a key is pressed and store it in the
variable.
WaitForKey duration (command)
Wait until a key is pressed for no more than duration seconds.
If no key has been pressed after the given time, evaluate the
command. Otherwise, leave the key in the keyboard buffer. See
also the paragraph on the format of durations.
Input (variable (max-length))
Read a return-terminated string from the keyboard and store the
result string in variable (without the terminating return). If
max-length is given, do not allow the user to enter more than
this number of characters.
See also GetPasswd under Security-related commands.
OnKey
Setup a key handler that will automatically evaluate the given
command when the key "c" is pressed (except is explicitely
waited by a GetChar or an Input command). If the string
"default" is used instead of a single character, the command is
executed if any other key is pressed.
5.1.8. Text output commands
This section lists commands used to perform regular text output. All
these commands can be used in graphic mode also, with the same
behaviour (except that text mode provides 80x25 characters while
graphic mode provides 100x37, because graphic mode characters are of
size 8x16). Optional arguments are listed between parenthesis. See
also under National Language Support.
Print
Print the specified string/expression at current cursor position
and using current text attributes, then move the cursor. Add
"\r\n" to the end of the string to go to the next line.
TextAttr fg-color bg-color
Setup the text attributes. One can also put a single numeric
value representing both colors and defined as 16*bg-color+fg-
color.
If you need more fantasy, you can use LoadFont. See under
National Language Support.
At line,col (command)
Move the cursor position to the specified position and evaluate
the command if provided.
Example: At 10,20 Print "Gnats and rats !"
Clear (color (pattern-char (top,left,bottom,right)))
Fill the given text area with the given pattern-char (either a
string or the decimal ascii code). The area defaults to the full
screen, the pattern char defaults to the full block (ASCII dec
219) and the color defaults to black (clear screen). Move the
cursor to the upper left corner of the cleared area.
BpMenu backward compatibility commands
.ATT ()
.CLS ()
.DEF ()
.KEY
.POS (() )
.PWD
.WLN ()
.WRT
See InCom's manual for more infos. We wrote some time ago a program
program for editing menu files using this syntax, but it is
preferable to make your menus using the new explicit syntax. Note
that the .PWD command is not implemented because we do not now the
password crypting algorithm used by InCom GmbH.
5.1.9. Graphics output commands
This section lists commands used to perform graphic-mode output. For
the functions listed in this section, coordinates are given in pixels.
You can also use all text output commands (see above) in graphic mode.
Optional arguments are listed between parenthesis.
Note that the graphic mode is automatically turned on whenever a
graphic command is used, unless the variable VESA is set to "OFF".
InitGraph (
Turn on VESA graphics. The origin is on the upper-left corner
of the screen (0 0). VESA graphics may hang some computers
under Windows 95. Run MrBatch with the -v option to avoid such
problems.
You can request a specific video mode if you use the parameter
"mode" This parameter is optional: if you do not specify any
value, the video mode will be taken from the first field of the
VESA-Modes variable.
Valid modes are :
· 640x480 => 640 by 480 pixels, 256 colors
· 800x600 => 800 by 600 pixels, 256 colors (default mode)
· 1024x768 => 1024 by 768 pixels, 256 colors
· 1280x1024 => 1280 by 1024 pixels, 256 colors
The VESA-Modes variable lists the video modes supported by your
hardware.
Example: InitGraph "640x480"
CloseGraph
Close VESA graphic mode and go back to text mode.
DrawBar x-pos y-pos width height color
VESA graphics. Draw a filled bar of the given size and colors.
DrawWindow x-pos y-pos width height (bg-color (bar-color)) (
VESA graphics. Draw a window of the given size and colors. The
background color defaults to LightGray and the title-bar color
defaults to Blue. If you include a title string and a color,
this text will be displayed in the title bar.
Drawtext x-pos y-pos
VESA graphics. Draw the text string at the given position with a
transparent background. The color defaults to text foreground
color.
DrawGif
VESA graphics. Load the given GIF-87a file and draw it on the
screen. The file can be interlaced, but must be in GIF-87a (not
GIF-89a). The image size should fit in the selected video mode.
You cannot load a 1024x768 GIF file when you selected a 640x480
mode. The GIF position defaults to the top left corner of the
screen (0 0).
The color-strategy defines the allocation of colors in the
palette when more than 256 colors are needed (for instance when
two 256 colors GIF files are displayed simultaneously):
· Best-Colors use best possible colors for the most recent GIF
· Spare-Colors try to avoid allocating colors, change existing
colors
· Share-Colors try to avoid allocating colors, use existing colors
· Reuse-Colors allocate no new color, only use existing colors
The default strategy is Best-Colors.
5.1.10. Security-related commands
This section lists commands that help you authenticate a user.
Optional arguments are listed between parenthesis.
Some of these functions cooperate with a Security gateway, that you
should first install. See the section on Special TFTP servers for more
infos.
GetPasswd (variable (max-length))
Same as Input, but echo stars instead of the typed characters.
Crypt
Apply the Unix crypt function to the given 8-chars text and
store the resulting crypted string into variable. The "salt" is
usually a two-character string that will be found as the first
two characters of the crypted string.
Note that Unix crypt is a one-way function. It is not possible
to decode the crypted string. One can only try to crypt another
string with the same salt and compre the resulting crypted
string.
DESCrypt
Crypt the given text using the given 8-chars key and store the
result as an hexadecimal string in variable.
DESDecrypt
Decrypt the given hexadecimal string using the given 8-chars key
and store the result in variable.
MD5
Compute the MD5 checksum of the given text and store it as an
hexadecimal string in variable. Can be used as an alternative to
the Unix crypt function to check for passwords bigger than 8
characters.
CheckUser
Connect to the $Security-Gateway and check if the given user
exist in the given radius domain and uses the specified
password. If the domain is "Unix", use the Unix user/password
definition on the security gateway. For any other domain, use
the security gateway domain definition file to determine the
real Radius or NT domain to check.
Set the value of $Security-Check to "PASSED" or "FAILED". The
password do not transit in clear on the network.
5.1.11. Disk-related commands
This section lists commands for preparing the hard-disk. Optional
arguments are listed between parenthesis.
GetPartitions variable (disk)
Read the partition table(s) for the given disk and store it as a
string into the given variable. The result string is a space-
separated list of Type:Size, where
· Type is FAT16, EXT, BIGDOS, NTFS, FAT32, FAT32-LBA, BIGDOS-LBA,
EXT-LBA, LINUX-SWAP, LINUX-EXT2 or the decimal filesystem id for
unknown types.
· Size is the size of the partition in megabytes.
See SetPartitions for more informations about partitions.
SetPartitions
Setup the partition table(s) to the content of the string. The
format used is the same that for GetPartitions. This command
also reset all boot flags (hint: use SetBootPart).
The main partition table in the master boot record (MBR) has
only four entries. Moreover, DOS and Windows accept only ONE FAT
partition (called the Primary partition, C:) in the main
partition table. Any supplemental FAT partition should be nested
in an extended partition (and is thus called a Logical
partition). If we give numbers 1-4 to the partitions described
in the MBR partition table and numbers 5-8 to the partitions
described in the first extended partition, the definition of two
FAT partitions would work by defining partition 1 as FAT,
partition 2 as EXT and partition 5 as FAT. Partitions 3,4,6,7
and 8 should be marked as UNUSED. The same scheme can be used
recursively to define more than two FAT partitions: nesting
another extended partition in partition 6 and adding a logical
FAT partition in partition 9.
In the most strict interpretation of DOS specifications, that
means that entries 3 and 4 of the partition tables are never
used. In practice, some versions of DOS and some other OS are
able to use more than two partitions per partition table, but
there is no clear rule. On this side, BpBatch is rather
flexible in its interpretation of partition tables, it can often
understands things that OSes cannot.
One universal rule is that there should never be more than one
extended partition per partition table, otherwise the partition
numbering scheme breaks down.
If you want to try funny configurations, make your own
experiments, but don't complain if the OS does not recognize
your partitions. The only way it is guarantee to work is to use
the primary partition to store the OS boot partition, and to
nest all other partitions, one at a time, in extended
partitions.
Example of extended partitions :
SetPartitions "BIGDOS:100 EXT:400 EMPTY EMPTY BIGDOS:400"
GetBootPart variable (disk)
Get the partition number with the boot flag turned on (DOS says:
the activated primary partition) and store it to the variable.
The first partition is numbered 1. If no partitions has the
boot flag turned on, answers zero.
SetBootPart partition (disk)
Set the boot flag to the given partition. The boot flag let the
master boot record (MBR) choose which partition to boot on. The
first partition is numbered 1.
Blank partition (disk)
Fill the given partitions with zeroes. Can take quite a lot of
time for big partitions. Do not format the partition for any
operating system. See also Clean.
Clean partitions (disk) (
Fast-format the given partition(s) according to the type
declared in the partition table. If a label is given and the
filesystem supports it, setup the partition label. For a
paranoiac full format, call Blank on the partition first.
Clean is supported for (FAT16) BIGDOS, FAT32, EXT, LINUX-EXT2
and LINUX-SWAP partitions. To clean the master boot record
(MBR), use Clean 0.
Clean should be used on data partitions and on MBR/EXT
partitions. It is totally useless to clean a partition before
unzipping a filesystem on it using FullUnzip.
FullUnzip
Decompress a full disk archive to the given partition,
overwriting any existing file (clean-up on the fly).
FullUnzip is supported for (FAT16) BIGDOS, FAT32 and LINUX-EXT2.
This commands turn on VESA graphics to display a progress
banner, unless VESA has been turned OFF.
IncrUnzip
Decompress an incremental disk archive to the given path. Files
in the archive replace those with the same name on the target
path, but other files are not deleted.
IncrUnzip is supported for (FAT16) BIGDOS, FAT32 and LINUX-EXT2.
This command is far less efficient than FullUnzip since the
existing filesystem structure must be preserved. However, it
avoids multiplying the number of different disk images by
storing the differences only.
FileUnzip
Uncompress a file previously compressed with MrZip FileZip
command. The file is validated by a 32-bits CRC.
Copy
Copy the source file to the destinaton file, byte-to-byte. Can
be used after a FullUnzip for instance to update configuration
files from the server without rebuilding the image. Better to
use FileUnzip for big and easy-to-compress files.
Append
Copy the first, then the second file to the destination file,
byte-to-byte. Can be used on arbitrary large files. The
destination file cannot be one of the two source files.
Patch
Read the source file and perform variable substitution before
writing it to the destination file. The interpretation of
characters above ASCII 127 depends on the value of $IsoLatin.
By default, variables are recognized when prefixed by "${" and
postfixed by "}". This can be changed to any other non-empty
string. remember that if you want to use a dollar sign within
the prefix or suffix, you must escape it or it will get macro-
evaluated. For instance, if you want to explicitely use the
default prefix and postfix, use:
Patch "source-file" "dest-file" "\${" "}"
MkDir
Recursively create directories from the root to the given full
path. If the path already exists, this command has no effect.
Delete
Remove the given file. The file must exist.
DelTree
Recursively remove all files and directories under the given
path, and remove the directory itself.
5.1.12. Boot commands
This section lists commands for continuing the boot process. Optional
arguments are listed between parenthesis.
HideBootProm
Restore the memory and the interrupt vectors allocated by the
bootprom. All attempts to make TFTP transfers will fail after
calling this command. It is usually a good idea to call this
command before HdBoot, or you might run short of memory under
DOS/Windows. This command is implicitely called by FloppyBoot.
Note that although this function restore all vectors
"officially" rerouted by the BootProm, it does not seems to
restore everything. But it works well enough for DOS and
Windows.
LoadRamDisk
Load a floppy disk image into the extended memory and redirect
the BIOS Disk Services to make floppy disk calls use this image
instead. This command implicitely calls HideBootProm. Call
FloppyBoot to boot on the ramdisk you just loaded.
This kind of ramdisk may not be as robust as what you get when
you use the TFTPBoot command. The only advantage is that it only
steals a few hundred bytes of conventional memory instead of the
>64 KB reserved by the TCP/IP BootPROM. Warning, nothing secures
the extended memory in which the ramdisk resides. There is no
way to uninstall such a ramdisk.
LoadZRamDisk
Do the same as LoadRamDisk, but for an image that has been
compressed using MrZip FileZip command. Compressed ramdisks are
protected against data corruption (and uncomplete download) by a
byte count and a 32-bits CRC.
TFTPBoot
Chain to another boot file (for instance a floppy image made
with InCom's BpShell program). See the file referencing
conventions for accessing a file on another TFTP server.
FloppyBoot
Hide the Boot ROM, load the floppy disk boot sector and boot on
it.
HdBoot (disk)(:partition)
Load the given boot sector and boot from it. The disk default to
zero, the first hard disk, and the partition defaults to zero,
ie. the master boot record. You can boot from any partition, but
be warned that Windows 95 may not let you boot a partition that
has not been set as the boot partition (hint: use SetBootPart).
This command does not implicitely call HideBootProm, so you
might want to call it before.
LinuxBoot
Load the given kernel and ramdisk into the high memory, setup
the command line and boot the kernel. It is a good idea to put
at least a minimal command line with the location of the root
filesystem (like "root=dev/hda1"/). If you are using a linux
system that heavily relies on lilo (like RedHat Linux 5.1), it
may be necessary to add to the command line something like
BOOT_IMAGE=linux. Note that the kernel can be loaded by TFTP
(automatically cached on the hard disk) or directly from the
target root partition.
This command works for small and big kernels (zImage and
bzImage).
5.1.13. National language support
This section lists commands related not national language support.
Optional arguments are listed between parenthesis.
RemapKeys
National keyboard support. Remap given keys to other characters.
For instance, to swap the Y and Z keys, use
Remapkeys "yzYZ" "zyZY"
It is a good idea to use the quoted octal notation when using char­
acters not included in the minimal ASCII character set, in order to
avoid a dependency to the iso-latin modal settings.
For international keyboards, there are two keys that produce a
backslash in non-remapped (US) mode. Each of them can be
independantly remapped, thanks to the fact that BpBatch sees one of
them as a key answering ASCII code 252 (octal) or ASCII code 335
(octal) when shifted.
If you send me a sample script that does keyboard mapping for your
national keyboard, I will make it available under
http://cuiwww.unige.ch/info/pc/remote-boot/soft/sample-scripts To
help you make your own keyboard mapping, I suggest pressing all
special keys without remapping the keyboard and writing down the
character they produce. These will be the original-keys. The
remapped-keys simply are the key you would have liked to see, in
the same order. If some keys (either original or remapped) produce
characters above ASCII dec 127, use the quoted octal notation. You
can easily get the octal code for any given character by looking in
the ASCII table of HelpPC for instance (HelpPC is a shareware
hypertext on-line help program by David Jurgens).
RemapAltkeys
National keyboard support. Remap the given keys when ALT is
depressed For instance, to map Alt-2 to the ampersand sign, use
RemapAltKeys "2" "@"
Note that dead keys are not supported.
LoadCodePage
Load and activate the given binary Codepage file. Codepages are
used for the translation of Unicode characters (present on VFAT
valumes for instance) into 8-bits characters. If you do not
have the right Codepage loaded, you will get FAT warnings while
accessing the filesystem when special characters are encountred.
All binary codepage files are available at
http://cuiwww.unige.ch/info/pc/remote-boot/soft/codepage.zip
The default codepage is 850, a reordered superset of ISO-
Latin-1. If you load a more exotic codepage, you should usually
turn the variable $IsoLatin to "off" or you might get
meaningless implicit conversions. Moreover, if you want to
display exotic characters, you should also load the proper
screen font (use "LoadFont").
LoadFont
Load and activate a VGA/VESA font, both in text and graphic
mode. The font file must be a binary file of 16
bztes/characters (8x16 bitmap). This command can be used for
National Language Support as well as for Fantasy support.
An archive with several fantasy fonts is available at
http://cuiwww.unige.ch/info/pc/remote-boot/soft/fonts.zip. This
archive also contains a program to extract fonts for your
codepage from the DOS .CPI file.
5.1.14. Commands specific to MrZip
Source...
Source (i)archive "filename"
Source path "path"
Set the source for the archive manipulation to the given
(incremental) archive file or disk path.
Dest...
Dest (i)archive "filename"
Dest (i)dump
Dest path "path"
Set the destination for the archive manipulation to the given
(incremental) archive file, dump or disk path. To control the
quantity of data displayed during dump, use the $DumpFormat special
variable.
FileZip
Compress a file for further decompression with FileUnzip or for
using as ZRamDisk. The file is validated by a 32-bits CRC.
Filter...
Filter -"pattern"
Filter +"pattern"
Avoid/allow files and directories matching the given pattern
(wildcards allowed) to be included in the archive. The pattern is
matched agains the full pathname. By default, all files are
included in the image. You only need to explicitely allow files
that where cancelled by a filter. Each negative filter has its own
positive filter (allowed) sublist.
For DOS/Windows images, you will typically use
Filter -"*.swp"
Filter -"temp/*"
and for Unix images, you will typically use
Filter -"var/log/*"
Filter -"tmp/*"
CopyArchive
Start the archive manipulation operation, according to source,
destination and filter settings. Except in a few circumstances,
you will probably use the shortcut below instead of explicitely
calling CopyArchive. One circumstance in which you will use
CopyArchive explicitely is when you want to change the
fragmentation of an image, as follow:
set FragmentSize="30 MB"
Source archive "original.imz"
Dest archive "refragmented.imz"
CopyArchive
FullZip
Shortcut for
Source path "path"
Dest archive "full-archive"
CopyArchive
You should usually first setup filters.
IncrZip
Shortcut for
Source path "path"
Dest iarchive "incr-archive"
CopyArchive
FullDump
Shortcut for
Source archive "full-archive"
Dest dump
CopyArchive
IncrDump
Shortcut for
Source iarchive "incr-archive"
Dest dump
CopyArchive
XCopy
Shortcut for
Source path "srcpath"
Dest path "dstpath"
CopyArchive
5.2. NoBreak.sys
Nobreak.sys is a very small (about 350 bytes only) driver that you
include at the beginning of your config.sys. Its goal is to secure the
boot process, until the user is logged in. DOS provides a setting for
this (namely BREAK=OFF), but it is not drastic enough, and has almost
no effect in the autoexec.bat. Our driver works by modifying the
scan-code of the key pressed when a break is requested, directly at
the BIOS level. This way, no program at all can receive a break until
break is enabled again.
The driver must be loaded from the config.sys (or using the devlod
program from Undocumented DOS). Afterwards, break can be enabled by
sending Yes to the NOBRK pseudo-device, and disabled again by sending
No (in fact, only the first character, Y or N is significant).
As this driver relies on the BIOS, it does only work for DOS and
Windows 3.1. Windows 95 has its own low-level keyboard handling
routines.
Assembler source code is available.
6. Special TFTP Servers
As the only network support available in the TCP/IP BootPROM is TFTP,
there is a special interest in enhancing TFTP servers for providing
new capabilities.
6.1. Incom Enhanced TFTP Server
InCom GmbH distributes with the TCP/IP BootPROM an enhanced TFTP
server that can send packets of up to 1408 bytes instead of the
standard 512 bytes. This is a great enhancement that you should use.
This server is available on the TCP/IP Bootprom Utility disk for
Solaris, Windows and as Netware NLM.
6.2. Linux Enhanced TFTP Server
We built a modified version of Linux TFTP server that acts as InCom
enhanced TFTP server. Basically, we simply changed the packet size
from 512 to 1408 bytes and the port from 69 to 59. It is available
from http://cuiwww.unige.ch/info/pc/remote-boot/soft/etdtpd.tar.gz.
6.3. The Security Gateway
We wrote a special TFTP server that serves as security gateway for
authenticating users. This server runs under Linux or Solaris, and can
authenticate users according to a Unix password database (NIS and
shadow passwords are supported), a Windows NT (or Samba) server or a
Radius server. It is available from
http://cuiwww.unige.ch/info/pc/remote-boot/soft/stdtpd.tar.gz, with
source and precompiled binaries. The precompiled binaries do not
include NT password encryption as we cannot distribute libdes but
compilation is straightforward.
In order to use the security gateway, you just have to setup a trivial
security domains configuration file that describes to which
authentication server each logical security domains maps (the Unix
domain implicitely maps to the server Unix password database). This is
a sample configuration file:
______________________________________________________________________
#
# STFTPD configuration file
#
# This file specify the server of the "security domains". Two types of
# authentication servers are supported : radius or winnt (winnt includes
# NT Server and Samba)
#
# Format of radius servers
# radius
#
# secret is the secret word as specified in your /etc/raddb/clients file
#
# Format of SMB servers
# winnt
#
# netbiosname is the NETBIOS name of your server
#
# Examples
radius sec-dom-rad radiusserver testing123
winnt sec-dom-nt1 192.168.1.1 NTSERVER1
winnt sec-dom-smb samba SAMBA1
______________________________________________________________________
Note that if you are using Samba, you must set security = user.
You can also provide to the security server a file containing a list
of users which are not allowed to log on (for which the check will
fail anyways).
6.4. The Broadcast TFTP Server
We wrote a special TFTP server that implements a home-made Broadcast
variant of TFTP. Using this server, we were able to download images to
25 clients on a heavily loaded 10 Mb ethernet network at 6 Mb/s (it is
more efficient than the regular TFTP because it does not need to
acknowledge each packets). This server runs under Linux or Solaris.
It is available from http://cuiwww.unige.ch/info/pc/remote-
boot/soft/btdtpd.tar.gz, with source and precompiled binaries.
As the TCP/IP bootprom does not support this protocol, our solution
consist in booting a tiny ramdisk-based linux system using the tools
described in this document, and running the Linux version of MrBatch
which has built-in support for Broadcast TFTP. A simple batch file can
the download all files to the cache in a few minutes, simultaneously
on all client computers. You do not need to install Linux yourself to
use this package, except if you have exotic hardware and cannot
directly use the kernel provided in the package.
The process works as follow. First, you startup the broadcast server
manually, giving the number of expected client computers as argument
(remember, this procedure is not to be used every day but only when
you changed an image and want to ensure it is immediately uploaded to
all your client computers). Then, you turn on all client computers,
which will run the following BpBatch script:
______________________________________________________________________
#
# This batch is run by bpbatch to launch a mini-linux using an initial
# ramdisk, which will then run mrbatch under linux.
#
# The broadcast TFTP protocol only works with the Linux implementation of
# mrbatch, because of the lack of broadcast support in the bootprom itself.
#
# 1. Setup a tiny partition, to let a lot of space for the cache
setpartitions "BIGDOS:50"
# 2. Clean the MBR
clean 0
# 3. Run a Linux Kernel with initrd (Initial Ramdisk) supprt, and use
# bcastrd.gz as the initial ramdisk (will be mounted root and then
# executed via /linuxrc). See initrd.txt for more details about
# initial ramdisks. You don't have to specify a root device (second
# parameter is null) to the kernel, it will use the initial ramdisk.
linuxboot "linux.krn" "" "bcastrd.gz"
# 4. The initial ramdisk will run dhcpcd to setup networking using DHCP.
# It will then run mrbatch -w bcastlx
______________________________________________________________________
The initial ramdisk contains:
· dhcpcd, a DHCP client used to setup networking
· mrbatch
· linuxrc, a little wrapper automatically started by initrd and that
starts dhcpcd then mrbatch.
· usr/lib/terminfo/l/linux, used by MrBatch
· dev/*, devices needed to run Linux and mrbatch
All programs are statically linked and stripped, to avoid libc.so
which is really huge. The resulting ramdisk is Gzipped and takes
less than 300 KB. The kernel itself takes 450 KB (with many network
cards and initrd support). When Linux is up and running, MrBatch
is called with the following script (that you should edit for your
needs):
______________________________________________________________________
# This file is executed when mrbatch is launched by the initial ramdisk
# bcastrd.gz
# It's main purpose is to "broacast copy" files to the cache
#
# 1. Be verbose
showlog
# 2. Don't want a "press a key"
set pauselog="OFF"
# 3. Set partitions at their final values.
# Important: Since you will copy files into the cache to be used in future
# boot, you need to specify the same partitions as in the future boots.
setpartitions "BIGDOS:1024"
# 4. Clean the CACHE partition
clean -1
# 5. And the copy files into the cache, using the Broadcast TFTP protocol
# (port 99)
#
# You can use the script "as is", but you surely need to modify the following
# line ! In our example, we download the file mblinux.imz, which is the image
# file for our installation of Linux.
copy "$BOOTP-Server-IP@99:mblinux.imz" "{:-1}mblinux.imz"
______________________________________________________________________
When the transfer is done, you can simply turn off all client comput­
ers and change their initial boot script to your favorite menu.